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The present invention relates to computer systems; more particularly, the present invention relates to powering hard disk drives.
A hard disk drive (HDD) is a permanent storage device within a computer system that is used for data and the programs used to create the data. A HDD typically includes individual platters covered on both sides with a magnetic material. An HDD operates by writing small magnetic charges onto the surface of the disk platter. The platters spin at thousands of Revolution per Minute (RPM). Generally, a HDD requires in excess of two amperes (2 A) at 12 Vdc (or a 24 W power input) during the time the disk platter goes from zero RPM to its maximum RPM. The time required for a HDD to reach its maximum speed may take up to three seconds.
Ordinarily, the power supply for the computer system can easily manage the power requirements for starting a single HDD. However, in system applications where multiple HDDs are used, the power supply is typically designed to accommodate the startup of all HDDs at once. For example in a system employing four HDDs, it is necessary for the system power supply to be capable of managing in excess of 96 W (e.g., 24 Wxc3x974) of power at 12 Vdc. A power supply that is capable of handling such high power requirements is not cost effective for installation within a computer system. Therefore, a method to reduce the power needed to startup HDDs in a computer system is desired.
According to one embodiment, a method and apparatus is disclosed for powering up hard disk drives. According to one embodiment, the method includes staggering the startup of hard disk drives (HDDs) in a computer system including a plurality of HDDs.